Starting-rheostat.



No. 843,735. PATENTED. FEB. 12, 1907. L. S. CHAPMAN.

STARTING RHBOSTAT. urm'oumn FILED JUNE 9.1906.

- trolling electric-motor circuits, and has for ing either an sal is made quickly and that the motor, acting-magnet.

' sistance in series.

' rovide in connection with UNITED STATES PATENT, OFFICE, I

ERAL ELECTRIC COMPANY,

A CORPORATION OF NEW YORK.

STARTING-RHEOSTAT.

Specification of Letters Patent.

Patented Feb. 12,1907.

Application filed June 9,1906. $erial No. 321,001.

To all whom it mag concern:

Be it known thatl, LEWIS S. CHAPMAN, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Starting-Rheos tats, of which the following is a specification.

This invention relates to devices for con its object'the provision of a device of this character which will protect the motor against accidents 'due to careless handling and other causes in a reliable, safe, and efiicient manner.

My invention relates more specifically to protective devices for electric-motor. circuits.

In the use of motor-starting devices havunderload or overload releasemagnet in COHIlBCtlOD. with a reversingswitch it oftentimes happens that the revering as a generator, will retain the controllingarm in running position for a short time. During this interval if the switch is thrown over to the reverse position the motor may be destroyed by a dangerous rush of current, due to the fact that there is no protective re- This might also happen with a non-reversing switch which is opened and closed quickly. f

It is the object of my invention, therefore, to provide a device which will positively preventthe occurrence of such an accident. In carrying out my invention, therefore, I

i the reversingswitch on amotor-starting panel, means whereby when the reversing-switch is open the retaining-magnet ofthe starter is short circuiied, making the return of the arm to off position absolutely certain. When the switch is then thrown over to the reverse position, the short circuit of the magnet is again opened, thereby energizing the retainln the accompanying drawings, in which I have shown one embodiment of my invention, Figure 1- is a plan view of a startingpanel embodying my improvements. Fig- 2 is a detail of the reversing-switch, and Fig. 3 is a diagram of the circuit connections.

Referring to the-drawings, is a slate or.

' ply comprises a series of contacts 1 ype{ to center coi'itact 17 soapstone base of a starting-panel prov ded with a startii g-rheost'at, a reversing-switch, l

The starting-switch sim- 1, forming terminals for starting resistance 12, a starting-arm 13, pivoted at 14 for engagement with the contacts 11, and no-voltage magnet 15 for retaining the arm in running position. The lineswitch 16 is of the usual preferably a double-pole knifeswitcn wnile the reversing-switch may be of any desired type, but is also preferably a double-pole knife-switch pivoted at 17 and 18, so as to provide a double'throw for reversing the current. In Fig. 2 I have shown a detail of this switch, which is designed to short-circuit the retaining-magnet 15 when and a line-switch.

it is open. The switch blades are pivoted so as to engage clips 19 and 20 on one side of the pivot and clips 21 and 22 on the opposite side thereof.

For the purpose of closing a short circuit through the retaining-magnet I provide a plunger 23 directly under the cross-bar 24 of the switch and arranged to slide back and forth through the switch-base 10. A spring contact-strip 25 is secured under the pivotal point of the switch by means of bolts 26 and normally closes a metallic contact with the conductors 27- and 28 through the contacts 29 and 30, respectively. \Nhen, however, the switch is closed, the circuit between the. contactor 27 and springcontact 25 is opened on the side corresponding to the position of the switch, this being accomplished by the cross-bar 24L forcing the spring-contact 25 away from the contact 29 through the agency of the plunger 23. closed by the opening of the switch, the springcontact 25 forces the'plungerup and makes contact at 29. A similar operation takes place on the opposite side, so as to open and close the circuit between the spring-contact 25 and the conductor 28 at coritact 30. The arrangement of circuits with the reversing-switch in the position shown and the moved to starting posicontrolling-arm- 13 tion is as follows: Current passes from the When the plunger is I positiye main at 31 through the line-switch to' ce clip 19, thence through thereversing-switch V thence through wire 32, armature 33, wire '34, controlling-arm 13, starting resistance 12, wire 35, contact 18, contact 20, wire 36, wire 37, through the line' switch, and back to line at 38. The field 39' is connected across the line from 4D and 41. The starting-arm being moved to running position will be retained in this position by the magnet 15, which is connected across the -sition,- this circuit is again opened, thereby reenergizing the magnet.

It will thus be seen that I have provided a simple and convenient arrangement for preventingthedestruction of a motor by the careless use of a reversing-switch It should be understood, of course, that the device is capable -of use in'other connections than that shown and that many mo:iifications of the particular device which I have shown for purposes of illustration will-suggest themselves to those skilled in the art without departing from the spirit of my invention as set forth in the annexed claims.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. The combination with a starting-riled stat havinga no-voltage magnet, of a reversing-switch, and means controlled vthereby for deenergizing the said magnet.

2. The combination with a starting-rheostat, having a no-voltage magnet, of a switch in the motor-circuit, and means controlled bythe opening of said switchfor shortcircuiting the said. magnet.

3. The combination with a starting-rheostat having a no-vol'tage magnet, of a reversing-switch, and means controlled by the opening'of said switch for short-circu'iting the said magnet.

\ 4. The combination with a starting-rheostat having a nooltage magnet connected across the line; of a reversing-switch in the motor-circuit, and -means controlled by the actuation of said switch for deenergizing the said magnet.

5. The-combination with a starting-rheostat having a no-voltage magnet connected across the line, of a reversing-switch 1n themotor-circuit, and means for short-circuiting the said magnet on the openin g of said switch.

6. The combination with an electric motor, of a switch in the motor-circuit biased to openposition, an electroresponsive device for maintaining said switch-in the closed position, a reversing-switch, and means for deenergizing the said electroresponsive device on the actuation of said reversing-switch.

7. The combination with an electric m0- tor, of a switch in the motor-circuit biased to open position, an electromagnetic device responsive to no voltage connected across the line and arranged to maintain said switch in the closed position, a reversing-switch, and

means for denergizing the electromagnetic device by the actuation of the said switch.

8. The combination with an electric m0- -tor, of a switch in the motor-circuit biased to open position, an electromagnetic device responsive to no voltage connected across the line' and arranged to maintain said switch in the closed position, a reversing-switch, and

means for short-circuiting said electromagnetic device by the opening oi said reversingswitch. r Y

In witness whereof I have hereunto satiny hand this 8th day of June, 1-906. v

LEWIS S. CHAPMAN.

Witnesses:

BENJAMIN. 'B. HULL,

HELEN ORFORD. 

